Instruments have long been used in the transportation industry for providing information to the operator about the status of a vehicle's internal systems. Instruments which measure characteristics such as the amount of fuel in the fuel tank, the number of revolutions per minute of the engine, or the number of miles per hour being traveled are all very commonly used on a variety of vehicles, including boats, cars, trucks, and even construction equipment.
The number of instruments per vehicle varies considerably. The typical vehicle generally includes four instruments, but many vehicles include more. For example, boats and heavy-duty trucks often require as many as ten instruments, owing to the number of engines per vehicle and the variety of information which is of interest to the operator. Whatever their number, each of these instruments must be firmly mounted to the surface of the dashboard to minimize vibration relative to the operator such that the instrument's dial face may be easily read. Traditionally, this mounting has been accomplished by means of a collection of metal brackets which are mounted behind the vehicle's dashboard and which attach to the back of each of the instruments by means of screw terminals and threaded nuts. This method hides the instrument mounting from the operator, which is highly desirable for purposes of aesthetics and instrument longevity. Instrument installation and removal, however, are extremely difficult, because the back of the dashboard is not readily accessible. In fact, it may take an experienced technician in excess of an hour to assemble a single dashboard having multiple instruments. Much of this time is due to the fact that the dashboard must be completely removed from the vehicle in order to access its back side and the mounting mechanisms for the instruments.
An additional consideration when mounting an instrument is the visibility of that instrument to the driver, especially at night. For this purpose, many instruments have some form of light source within themselves which provides light to the dial face. In order to achieve the desired brightness and even distribution of light across the instrument face, current instrument designs typically include incandescent bulbs as the light sources. However, incandescent bulbs burn out as a matter of course and must be replaced over the course of the instrument's life, making it necessary to periodically access the instrument for bulb replacement. This is undesirable not only because of the inconvenience of removing the "rear-mounted" instrument from the dashboard, but also because of the mere inconvenience of having to replace the burned-out bulb in the first place.
It would thus be desirable to have an instrument assembly which can be securely mounted to the front of the dashboard with a hidden mounting mechanism which is easily accessible. Furthermore, it is desirable to have a lighting mechanism in the instrument assembly which evenly distributes light across the face of the instrument and does not need replacement as a matter of course. The present invention is directed at achieving these objectives.